Support SIGHUP for logrotate

[SystemKeeper]

When rotating garm.log the file handlers need to be re-opened. Currently we just do a restart of garm when we rotated the log. Would be nice if we could just send a SIGHUP (or something else) to gracefully to this without the need to restart.

[gabriel-samfira]

Hmm. If you specified the log path specifically and are not logging to syslog, garm should rotate automatically when it reaches ~500 MB or 28 days. See: https://github.com/cloudbase/garm/blob/main/util/util.go#L170-L176

We can also add a SIGHUP handler of course.

[SystemKeeper]

Oh I see. I wasn't aware of that build-in functionality... Hm, I think SIGHUP wouldn't hurt for people wanting to use logrotate, but I guess the build-in functionality should be be more visible in the future?!

[gabriel-samfira]

A lot more things should be more visible 🫣. I need to do a far better job at documenting.